Ever heard the saying, what you don't know can't hurt you? Or it's hard to believe what you can't see?

Well, what The Little Prince said is also true: "It is only with the heart that one can see rightly; what is essential is invisible to the eye."

We will not, however, go into an in-depth study of what children's book author Antoine de Saint-Exupery wrote in his classic work.

No, the concern here is why the air, which is supposed to be invisible, was not some days ago.

A troubling image from a doctor shared in a Viber group last week showed a white mask dirtied to gray at the end of the day.

At the time, news came out about the fog, smog, or vog that covered the metro after the Taal Volcano spewed ash anew.

"I stayed indoors at our hospital but was shocked that my N95 mask turned black! Mask-up everyone! Use N95, please," the doctor said.

Was Taal's ash to blame?

The Philippine Institute of Volcanology and the Department of Environment and Natural Resources said it was not.

The bad air quality could not have come from the volcano. "The vog (volcanic smog) [Philvolcs] detected from Taal Volcano is drifting west-southwest and, hence, is not going toward Metro Manila," one report said.

The wind direction that day negated assumptions that the hazy atmosphere was coming from Taal. What could it have been then?

Admit it. It's hard to take deep breaths in parts of Metro Manila because the air….just stinks. Yet what stinks even more is that the occasional smoke belcher can still leave a trail of gray smoke as it traverses our roads and highways.

We have the "almost invisible" traffic enforcer after the "no contact policy" was implemented to address the "kotong" issue — but, really?

Up to now, even with the Clean Air Act and environmental awareness, we still let a few lawbreaking loose cannons off to destroy our lungs.

Who's in charge of our air?

The DENR's Environmental Management Bureau, following concerns over the supposed vog, clarified in a statement: The air quality alert was "primarily attributed to emissions from heavy vehicular traffic, especially during rush hour."

Let me not go too ballistic about traffic, however. But then again, the so-called silver lining of the Covid-19 pandemic was the absence of road congestion. People doing "essential" runs or going to work as usual had one less thorn in their side — the internationally infamous Manila traffic.

We had stress-free road travel, and the air, oh, the air! People applauded the cleaner, clearer environment. It made some think of how the world would look without humans messing up the air quality.

Now traffic is "soooo back," if we are to say it like a hyped-up maniac, and we ask: why is it back? And also, what happened to our air?

We can talk about pollution now, but at the risk of another temperamental verbal vomit, let's recall when then-president Rodrigo Duterte clamped down on Manila Bay pollutants and, later, on Boracay's.

At the time, people reacted negatively to his rough language, but then again, think — why shouldn't he get nasty at those who had allowed "world-class" assets like Manila Bay and its sunsets, and Boracay and its fine white sand to become contaminated?

Why do we rant about petty matters when the bigger issues continue to fuel our aggravations?

Perhaps what is truly more toxic — almost poisonous — is neither the water we can't drink nor the air we can't breathe.

Maybe it's us. Let's take a deep breath and ponder on that.